blown headgasket? or not?

[blackturbobeast]

I'm a new-b to this forum and i might have a small problem maybe someone might be able to help me with and it goes as follows: I've got a d.s.s. 347 allum heads and a turbo, last night i changed the oil and noticed that it was really runny not thick...their wasnt any white residue. My stang runs hard and strong, doesnt miss or back fire, however when i stop at a light she'll die, but then 30seconds later will start right back up. she doesn't run hot stays at 180-190 and the oil pressure is at 70 when moving and roughly 55 at idle. Because of the stall outs and the runny oil nearly like water i was thinking that I had a blown head gasket. She doesn't smoke i'd like to add and the radiator fluid is full. I checked for bubbles in the radiator and NONE...anybody have any suggestions what I should look for to see if its a blown head gasket or what else i can do to test it? thanks for any suggestion some one might be able to provide me!!!!!!

[SpectorV]

you could put some trace stuff in your coolant that shows up under black light and then run it a bit. Drain the oil and see if any got into it~ then of course drain the coolant.

[Herbstang]

There are a few simple indicators you can check for with the engine cold and not running.

1. contaminated oil, it will have a milky appearance from the water mixing in the oil.
2. oil on the top of the coolant inside the radiator (if your vehicle has a remote header tank you may not get this)
3. have someone crank (remove the coil lead or disable the elcectronic ignition) the engine on the starter with the radiator cap or coolant jacket bleed hose/bolt removed, if the coolant pulses up and down or blows bubbles you could be in trouble.

If you find any of these symptoms move on to removing the spark plugs (lable the plugs and the leads as you remove them so you can put them back in the same place as you got them from) and again crank the engine on the starter, depending on how bad your head or gasket is gone you may get coolant or oil coming out of the plug holes. inspection of the plugs will also reveal problems during combustion, if you have rusty flaky deposits on the plugs you may be burning off water and if you have a heavy carbon your burning oil.

depending on the severity of the leak (and how hard you want to look for it)

if you have any of the first 3 items listed (water in oil, oil in water or pulsing coolant but dont get any result from checking the plugs change the oil and water as appropriate then warm up the engine without the radiator cap on (or the bleeder hose/bolt) and watch for bubbles as the engine warms up. Put tha cap back on the cooling system and take the vehicle for a short drive or run the engine till the entire system is up to temperature and then check the oil for contamination.

Having these symtoms is not always indicitaive of a blown head gasket and usually if the gastket is gone there is going to be some warping of the head and or block of the engine.

There are a few other things that can give similar symptoms to the ones listed above
1. internal damage to water/oil galleries
2. damage to oil/water intercoolers if fitted
3. weakened hoses on the cooling system can cause pulsations in the coolant
4. leaking valve seals may drop oil into the chamebers
5. poorly bleed cooling systems or systems where there are high loops in the coolant jacket may have some bubbling

[silverstangboy]

is it just the regular DSS shortblock? or did you go with one of the extreme X blocks?

all of the regular DSS blocks are just stock late model blocks... they won't hold up very well to a 70mm turbo, even if you have a huge restriction on the cam and intake.

I also wouldn't guess you have coolant in oil (even though I think herb covered that well) because it would be THICKER, white and milky.


back to your original question, how often do you change the oil, with that turbo, i'd go no more than a 1000 miles... runny oil is nothing more than used up oil. have fun and be careful.

[rocknbronco]

With the aluminum heads and the cast iorn block you could have an issue from the two having varied cool down rates.

[silverstangboy]

that would result with head lifting and an eventual blown gasket, you'd notice.